1. Field of the Invention
The present invention relates to a serial interface transmitting method, and more particularly, to a serial interface transmitting method which switches between a saving power mode and a normal mode.
2. Description of the Prior Art
People are surrounded by more and more mobile devices, such as smart phones, personal digital assistances (PDA) or tablet computers. To conveniently manage stored digital files inside the above mobile devices, or to share the digital files between the mobile devices or to backup the digital files, users connect the mobile devices to a personal computer to set up an electrical system.
Please refer to FIG. 1, which illustrates a conventional schematic diagram of an electrical system 10. As shown in FIG. 1, the electrical system 10 is utilized to provide the mobile device 104 with an operation of data transmission or data backup via a bus 102 and a master controller 100, so as to set up a personal digital database. Additionally, the master controller 100 is utilized as a control center to regard the mobile devices 1-n as peripheral devices 106 when the mobile devices 1-n are coupled to the master controller 100. Under such circumstances, the master controller 100 cannot only directly control the operations of the peripheral devices 106, but also provide the data transmission between the peripheral devices 106, so as to provide a better system management as well as an efficient data backup mechanism.
Since the master controller 100 can directly control the peripheral device 106 having serious power consumption, the master controller 100 needs to effectively control the power consumption of the peripheral device 106. In detail, the master controller 100 utilizes different buses 102 to communicate with one of the peripheral devices 106. First, the master controller 100 actively detects whether the peripheral device 106 is in a normal mode providing normal operations of the peripheral device 106 or an idle mode. If the peripheral device 106 is in the idle mode for a while, the master controller 100 sends a saving power signal to the peripheral device 106, accordingly, to turn off an operational clock source of the peripheral device 106, which means that the peripheral device 106 enters into a saving power mode. Similarly, the master controller 100 can send a waking signal to wake up the peripheral device 106 that is in the saving power mode, so as to restart the operational clock source of the peripheral device 106 and to enter into the normal mode for utilization of the master controller 100.
Please refer to FIG. 2, which illustrates a schematic diagram of related signals of the peripheral devices 106 while switching between different operational modes. As shown in FIG. 2, the peripheral devices 106 switches between a scanning state for retrieving data and a saving power state, and both states share the same operational period, such as 8.3 microseconds. When the peripheral device 106 is in the saving power state and the master controller 100 tries to utilize the waking signal (not shown in the figure) to restart the operational clock source CLK of the peripheral device 106, the operational clock source needs a period for stabilization. If the master controller 100 tries to communicate with the peripheral device 106 via the bus 102 for the data transmission before oscillations of the operational clock source CLK have stabilized, it has possibility to occur a data transmission loss because.
Therefore, it has become an important issue to provide an effective data transmission method, which provides higher efficiency while transmitting data between the master controller and the peripheral device which either has been in the saving power mode or is ready for entering into the saving power mode.